How Insulin Works in the Body How Insulin Works in the Body Search the site By Elizabeth Woolley - Reviewed by a board-certified physician. Updated November 14, 2016 Insulin has a hand in several processes in your body: Not only does it assist with metabolizing carbohydrates and storing glucose for energy in cells, but it also helps utilize the fat, protein, and certain minerals you eat. Because this hormone is so important in helping your body use the foods you ingest, a problem with insulin can have widespread effects on all of your body's systems, tissues, and organs—either directly or indirectly. If you have type 2 diabetes, learning how insulin works can help you understand why so many other medical conditions are associated with diabetes, why certain lifestyle practices are beneficial, and how your body reacts to food. Where Insulin is Produced in the Body Insulin is a hormone made up of a small polypeptide protein that is secreted by the pancreas, which acts as both an endocrine and exocrine gland. Endocrine glands are the system of glands that secrete hormones to regulate body functions. Exocrine glands aid in digestion.

The pancreas sits behind the stomach, nestled in the curve of the duodenum (the first part of the small intestine), and contains clusters of cells called islets of Langerhans. Islets are made up of beta cells, which produce and release insulin into the bloodstream. Insulin is Part of a Balancing Act Insulin affects carbohydrate, protein, and fat metabolism. Your body breaks these nutrients down into sugar molecules, amino acid molecules, and lipid molecules, respectively. The body can also store and reassemble these molecules into more complex forms. Insulin causes the storage of these nutrients, while another pancreatic hormone called glucagon releases them from storage. Insulin is involved in your body's careful balancing act to keep your blood sugar levels within a normal range. In simple terms: If your blood sugar is high: The pancreas releases insulin to help cells absorb glucose from the bloodstream to lower blood sugar levels. If your blood sugar is low: The pancreas releases glucagon to help the liver release stored glucose into the bloodstream to raise blood sugar levels. Blood sugar levels rise when most foods are consumed, but they rise more rapidly and drastically with carbohydrates. The digestive system releases glucose from foods and the glucose molecules are absorbed into the bloodstream.

The rising glucose levels signal the pancreas to secrete insulin to clear out glucose from the bloodstream. Insulin binds with insulin receptors on cell surfaces and acts as a key to open up the cells to receive glucose. Insulin receptors are on almost all tissues, including muscle cells and fat cells. Insulin receptors have two main components—the exterior and interior portions. The exterior portion extends outside the cell and binds with insulin. When this happens, the interior part of the receptor sends out a signal inside the cell for glucose transporters to mobilize to the surface and receive glucose. As blood sugar and insulin levels decrease, the receptors empty and the glucose transporters go back into the cell. Insulin and Type 2 Diabetes In a perfect situation, glucose from carbohydrates gets cleared rapidly. However, when there is insulin resistance , this does not happen, and sustained high glucose levels become a problem. Insulin resistance can be due to a problem with the shape of the insulin (preventing receptor binding), not having enough insulin receptors, signaling problems, or glucose transporters not working properly. Whatever the specific cause, the function of insulin is impaired. Insulin resistance develops before type 2 diabetes is diagnosed.

To make up for less effective insulin, the pancreas works overtime to increase insulin output. Eventually, some of the insulin works and blood sugar levels remain normal for a while. As insulin resistance worsens and the pancreas cannot keep up with the demand, glucose levels begin to rise and diabetes is diagnosed when levels get too high. How Insulin Affects Fat Metabolism Carbohydrate and fat metabolism are closely connected and both influenced by insulin. If insulin is not working properly, problems can occur. For example, high levels of insulin can send the wrong signals to the brain. These signals tell the brain that there is excess insulin and that your cells are starving for glucose. So in response, your brain creates cravings for carbohydrates, signals your body to store fat, and orders carbs to be burned for energy rather than body fat. This is why weight loss can be difficult when you have type 2 diabetes. Insulin also plays a key role in the development of high triglyceride levels: In the Liver: Insulin stimulates the creation and storage of glycogen from glucose. High insulin levels cause the liver to get saturated with glycogen. When this happens, the liver resists further storage.

Glucose is used instead to create fatty acids that are converted into lipoproteins and released into the bloodstream. These break down into free fatty acids and are used in other tissues. Some tissues use these to create triglycerides. In Fat Cells: Insulin stops the breakdown of fat and prevents the breakdown of triglycerides into fatty acids. When glucose enters these cells, it can be used to create a compound called glycerol. Glycerol can be used along with the excess free fatty acids from the liver to make triglycerides. This can cause triglycerides to build up in the fat cells. How Insulin Affects Protein and Minerals Insulin helps amino acids from protein to enter cells. When this process is hindered, it can make it difficult to build muscle mass. Insulin also makes cells more receptive to potassium, magnesium, and phosphate. These substances are also known as electrolytes, which help conduct electricity within the body. They influence muscle function, blood pH, and the amount of water in your body. An electrolyte imbalance can be worsened by high blood sugar levels as this can cause excessive urination with water and electrolyte loss.

Normal and Impaired Insulin Function To break things down in an easy-to-remember format, this list illustrates what happens with normal and impaired insulin function. Normal function: Insulin transports glucose into cells to clear glucose from the bloodstream. Impaired function: Glucose is not cleared from the bloodstream. Normal function: Insulin helps convert glucose to glycogen (the storage form of glucose) in liver and muscle cells. Impaired function: Glucose is not easily stored as glycogen. Cells "starve," which can cause the body to behave as if there are starvation conditions and even cause cravings for sweet carbohydrates, although there are high levels of glucose in the body. Normal function: Insulin slows down the creation of glucose from non-carbohydrate sources, like protein in the liver. An example of this is when the liver releases glucose into the bloodstream when blood sugar levels are too low. Impaired function: The liver releases glucose into the bloodstream inappropriately even when blood sugar levels are high. Normal function: Insulin stops the breakdown of fat and stimulates the creation of fat under the right circumstances. Impaired function: High insulin levels can signal for less fat loss and more fat storage.

Normal function: Insulin regulates the formation of fat from simple sugars, which can eventually become triglycerides . Impaired function Triglycerides levels increase inappropriately. Normal function: Insulin stimulates protein synthesis (creation), which affects muscle growth. Impaired function: You may have difficulty building muscle. How to Help Insulin Work Better These strategies may help you increase insulin sensitivity and reduce insulin resistance: What organ produces insulin? | Healthshare Q&A with Australian Health Practitioners What organ produces insulin? Wanting to know what organ produces insulin? 8 answers 13 Thanks I am qualified as a PHYSIOTHERAPIST and ACCREDITED EXERCISE PHYSIOLOGIST.I primarily use the McKENZIE METHOD for assessment and management of musculoskeletal pain disorders. The McKENZIE ... View Profile Hi edz! Insulin is produced by the pancreas. Why are you interested in knowing what organ produces insulin? Regards, Neil Thanks Reply to this post You must be a Healthshare member to reply to this post. Log in to your account or Sign up now (it's free). Advertisement Thanks Reply to this post You must be a Healthshare member to reply to this post.

Log in to your account or Sign up now (it's free). 6 Thanks I'm a Credentialed diabetes educator I work together with 2 endocrinologists. I'm specialized in type 1 diabetes, insulin pump therapy and sport and diabetes. I ... View Profile The pancreas has two functions it produce digestive juces and also insulin. Diabetes is a condition where you dont produce enough insulin. If you have issues with your pancreas like infections (pancreatitis) or some types of cancer you might risk develop diabetes. Both pancreatitis and pancreas cancer are quite rare but serious. Regards Inger Thanks Reply to this post You must be a Healthshare member to reply to this post. Log in to your account or Sign up now (it's free). Rochelle Thanks Reply to this post You must be a Healthshare member to reply to this post. Log in to your account or Sign up now (it's free). Counsellor, Diabetes Educator, Psychotherapist, Registered Nurse 0 4 Thanks Carolien Koreneff is a Somatic (body-oriented) psychotherapist, Health Coach, Counsellor as well as a Credentialed Diabetes Educator with nearly 20 years experience.

She currently sees ... View Profile As others before me have explained it is the pancreas that produces insulin, but not the whole pancreas! Only the beta cells in the pancreas produce insulin, so the development of diabetes is related to a beta cell function failure of some kind. In type 1 diabetes the beta cells are being “killed”, whereas in type 2 they are still present, but not working well enough. The pancreas also contains alpha cells which produce glucagon, the ‘antidote’ to insulin, so called because glucagon can release glycogen (stored glucose) back into the blood stream. People with type 1 diabetes often have both alpha and beta cell failure and this combination puts them at higher risk of hypoglycaemia. About Diabetes About Diabetes Updated:Sep 30,2015 "Diabetes mellitus," more commonly referred to as "diabetes," is a condition that causes blood sugar to rise to dangerous levels: a fasting blood glucose of 126 milligrams per deciliter (mg/dL) or more. How Diabetes Develops After eating a meal, the food is broken down by the digestive system and blood sugar (or glucose) rises.

The pancreas is an organ near the stomach, which produces a hormone called insulin. With the help of insulin, the body's cells take up the glucose and use it for energy. When your body does not produce enough insulin and/or does not efficiently use the insulin it produces, sugar levels rise in the bloodstream. When this happens, it can cause two problems: Right away, the body's cells may be starved for energy. Over time, high blood glucose levels may damage the eyes, kidneys, nerves or heart. Types of Diabetes There are two main types of diabetes: type 1 diabetes and type 2 diabetes. A family history of diabetes can significantly increase a person's risk of developing the condition. Type 1 Diabetes Type 1 diabetes is a serious condition that occurs when the pancreas makes little or no insulin. Without insulin, the body is unable to take the glucose (blood sugar) it gets from food into cells to fuel the body. People with type 1 diabetes must take daily insulin or other medications daily. For that reason, this type of diabetes is also referred to as insulin-dependent diabetes. Type 1 diabetes was previously known as juvenile diabetes because it's usually diagnosed in children and young adults.

However, this chronic, lifelong disease can strike at any age, and those with a family history of type 1 diabetes have a greater risk. Health Risks for Type 1 Diabetes During the development of type 1 diabetes, the body's immune system attacks certain cells (called beta cells) in the pancreas. Although the reasons this occurs are still unknown, the effects are clear. Once these cells are destroyed, the pancreas produces little or no insulin, so the glucose stays in the blood. When there's too much glucose in the blood, especially for prolonged periods, all the organ systems in the body suffer long-term damage. Learn more about the health consequences of diabetes and how to treat it . Type 2 Diabetes Type 2 diabetes is the most common form of diabetes. Historically, type 2 diabetes has been diagnosed primarily in adults. Today, however, adolescents and young adults are developing type 2 diabetes at an alarming rate. This correlates with the increasing incidence of obesity and physical inactivity in this population, both of which are risk factors for type 2 diabetes.

This type of diabetes can occur when: The body develops "insulin resistance" and can't make efficient use of the insulin it makes, and The pancreas gradually loses its capacity to produce insulin. In a mild form, this type of diabetes can go undiagnosed for many years, which is a cause for great concern since untreated diabetes can lead to many serious medical problems , including cardiovascular disease. Type 2 diabetes may be delayed or controlled with diet and exercise. Precursors to Diabetes In addition to full-blown diabetes mellitus, there are precursors to the disease: Insulin Resistance Insulin resistance is a condition that affects more than 60 million Americans. Insulin resistance occurs when the body makes insulin but does not use it efficiently and glucose builds up in the blood instead of being used by cells. To compensate for the high blood sugar levels, the insulin-producing cells in the pancreas release more and more insulin to try to keep blood sugar levels normal. Gradually, these cells fail to keep up with the body's need for insulin and blood sugar levels begin to rise. Insulin resistance can lead to both pre-diabetes and type 2 diabetes.

When a fasting individual has too much glucose in the blood (hyperglycemia) or too much insulin in the blood (hyperinsulinemia), it indicates a person may have insulin resistance. Pre-diabetes Pre-diabetes means that your blood sugar levels are higher than normal, but not to the levels to be diagnosed with diabetes. If you’ve been told by your healthcare provider that you have “pre-diabetes” it also means that without making some healthy changes, you have a higher risk of developing type 2 diabetes. Learn more about pre-diabetes . Health Risks of Insulin Resistance People with insulin resistance are at greater risk of developing type 2 diabetes and cardiovascular disease. They also are more likely to have a history of being obese and physically inactive and to have other cardiovascular risk factors such as dyslipidemia (too much) LDL ("bad") cholesterol , not enough HDL ("good") cholesterol , or high triglycerides , hypertension, and other factors that can increase cardiovascular risk. Untreated diabetes can lead to many serious medical problems , including heart disease and stroke. That's why it's important to be aware of the symptoms as well as the risk factors and to take appropriate steps to prevent and treat insulin resistance and diabetes.

This content was last reviewed August 2015. What is Insulin? - Important hormone allows your body to use sugar (glucose) What is Insulin? Written by Amy Hess-Fischl MS, RD, LDN, BC-ADM, CDE Insulin is a hormone made by the pancreas that allows your body to use sugar (glucose) from carbohydrates in the food that you eat for energy or to store glucose for future use. Insulin helps keeps your blood sugar level from getting too high ( hyperglycemia ) or too low (hypoglycemia). The cells in your body need sugar for energy. However, sugar cannot go into most of your cells directly. After you eat food and your blood sugar level rises, cells in your pancreas (known as beta cells) are signaled to release insulin into your bloodstream. Insulin then attaches to and signals cells to absorb sugar from the bloodstream. Insulin is often described as a “key,” which unlocks the cell to allow sugar to enter the cell and be used for energy. After you eat, cells in your pancreas are signaled to release insulin into the bloodstream.

If you have more sugar in your body than it needs, insulin helps store the sugar in your liver and releases it when your blood sugar level is low or if you need more sugar, such as in between meals or during physical activity. Therefore, insulin helps balance out blood sugar levels and keeps them in a normal range. As blood sugar levels rise, the pancreas secretes more insulin. If your body does not produce enough insulin or your cells are resistant to the effects of insulin, you may develop hyperglycemia (high blood sugar), which can cause long-term complications if the blood sugar levels stay elevated for long periods of time. Insulin Treatment for Diabetes People with type 1 diabetes cannot make insulin because the beta cells in their pancreas are damaged or destroyed. Therefore, these people will need insulin injections to allow their body to process glucose and avoid complications from hyperglycemia. People with type 2 diabetes do not respond well or are resistant to insulin. They may need insulin shots to help them better process sugar and to prevent long-term complications from this disease. Persons with type 2 diabetes may first be treated with oral medications, along with diet and exercise.

Since type 2 diabetes is a progressive condition, the longer someone has it, the more likely they will require insulin to maintain blood sugar levels. Various types of insulin are used to treat diabetes and include: Rapid-acting insulin: It starts working approximately 15 minutes after injection and peaks at approximately 1 hour but continues to work for two to four hours. This is usually taken before a meal and in addition to a long-acting insulin. Short-acting insulin: It starts working approximately 30 minutes after injection and peaks at approximately 2 to 3 hours but will continue to work for three to six hours. It is usually given before a meal and in addition to a long-acting insulin. Intermediate-acting insulin: It starts working approximately 2 to 4 hours after injection and peaks approximately 4 to 12 hours later and continues to work for 12-18 hours. It is usually taken twice a day and in addition to a rapid- or short-acting insulin. Long-acting insulin: It starts working after several hours after injection and works for approximately 24 hours. If necessary, it is often used in combination with rapid- or short-acting insulin.

Insulin can be given by a syringe, injection pen, or an insulin pump that delivers a continuous flow of insulin. Your doctor will work with you to figure out which type of insulin is best for you depending on whether you have type 1 or type 2 diabetes, your blood sugar levels,and your lifestyle. Endocrine System Organs, Glands | Hormones and Metabolism Disorders of the Endocrine System Endocrine Glands Glands are a group of cells that produce and release hormones directly into our blood stream in a process called secretion. There are 2 types of glands. Exocrine glands have ducts or channels which secrete chemicals such as saliva or sweat. Endocrine glands do not have ducts; they secrete hormones directly into the blood stream. Organs of the Endocrine System Hypothalamus The hypothalamus is located in the brain and links the nervous and endocrine systems to each other. It secrets hormones that put the pituitary gland into action. Pineal Gland The pineal gland is a small, pine-cone shaped endocrine gland in the brain. It produces melatonin, a derivative of serotonin, a hormone that affects wake/sleep patterns and seasonal functions.

Pituitary gland The pituitary gland, or hypophysis, is an endocrine gland about the size of a pea. It weighs less than an ounce and is one of the most important organs in the body. It is located at the base of the brain and is closely connected to the hypothalamus. The pituitary gland secretes nine hormones that regulate homeostasis by stimulating other endocrine glands to produce and secrete their own hormones. The pituitary gland has two components: the anterior (front) pituitary (or adenohypophysis) and the posterior (back) pituitary (neurohypophysis). The anterior lobe makes up most of the gland and releases the majority of the hormones. The smaller posterior lobe stores hormones but does not make them. It links the endocrine system with the nervous system by way of the hypothalamus.The pituitary gland is known as the ‘master’ endocrine gland. The hypothalamus controls the production of hormones in both lobes. The pituitary gland produces many important hormones, some of which act on other glands to make them produce hormones.

The pituitary gland releases at least 9 hormones that have important effects on the body—these include the thyroid stimulating hormone (TSH), adrenocorticotrophic hormone stimulates the adrenal glands. Thyroid The butter-fly shaped thyroid gland is one of the largest endocrine glands. The thyroid gland is in the front of the neck, just below the thyroid cartilage or “Adam’s apple”. The isthmus bridges the two lobes of the thyroid and is located below the cricoid cartilage. The thyroid gland controls how quickly the body uses energy (metabolism), calcium levels in the blood, how the body makes proteins, and how sensitive the body is to other hormones. It produces thyroid hormones, the principal ones being triiodothyronine (T3), thyroxine which can sometimes be called tetraiodothyronine (T4) and calcitonin. These hormones regulate the heart rate, the rate of metabolism and affect the growth and rate of function of many other systems in the body. T3 and T4 are made from iodine and tyrosine. Calcitonin slows down the rate at which bone is broken down decreasing the amount of calcium dissolved in the blood.

Parathyroid Gland The parathyroid gland controls calcium levels in the blood. The parathyroid is a small of glands around by the thyroid gland. They produce the parathyroid hormone or PTH, which increases the rate at which broke bone is broken down. As a result, more calcium is released into the blood. Parathyroid hormone works in partnership with calcitonin from the thyroid gland. The 2 hormones have the opposite effect. Through negative feedback they keep the calcium level in the blood stable. Hormonal output from the thyroid is regulated by the thyroid-stimulating hormone (TSH) produced by the anterior pituitary, which itself is regulated by thyrotropin-releasing hormone (TRH) produced by the hypothalamus. The thyroid gets its name from the Greek word for “shield” because of its shape. The most common problems of the thyroid gland are overactive thyroid gland, called hyperthyroidism, and an underactive thyroid gland, called hypothyroidism. Thymus The thymus is a specialized organ of the immune system. The thymus “educates” T-lymphocytes (T cells), which are critical cells of the adaptive immune system.

Adrenal Glands The small, triangular adrenal glands (also known as suprarenal glands) sit atop the kidneys . Each is divided into two distinct anatomic and functional organs. The adrenal cortex (the outer region which secretes corticosteroid hormones that affect metabolism (that is how food is stored and used), chemicals in the blood, and characteristics such as body shape and hairiness. The smaller, inner region—the adrenal medulla (which is part of the sympathetic nervous system)—is the body’s first line of defense against physical and emotional stress. They are mainly responsible for releasing hormones in response to stress through the synthesis of corticosteroids such as cortisol and catecholamines such as epinephrine (adrenaline) and norepinephrine. They also produce androgens. The adrenal glands affect kidney function through the secretion of aldosterone, a hormone that helps regulate the osmolarity of blood plasma. The adrenal glands help us deal with dress and as well as maintain homeostasis. Disorders of the adrenal glands include congenital defects such as adrenal hyperplasia, tumors, autoimmune disorders, infection, and impaired blood supply.

The adrenal cortex When looked at under a microscope, the adrenal cortex is made up of 3 distinct zones. the outermost zone secretes the hormone aldosterone, which inhibits the amount of sodium excreted in the urine, maintaining blood pressure and blood volume. The inner and middle zones together secrete hormones hydrocortisone, also called cortisol, corticosterone, as well as small amounts of androgen hormones. The rate of release and amount of secretion is controlled by other hormones made in the hypothalamus and pituitary. The adrenal medulla the adrenal major love is closely related to nervous tissue and secretes the hormone epinephrine and norepinephrine in response to stimulation by sympathetic nerves. these nerves are most active at times of stress. the release of these hormones increases the heart rate and why the airways in the lungs in order to pump more blood to the large muscles of the skeleton. The airways in the lungs are increased so that more oxygen can be taken in. As more blood is sent to the active organs less blood is sent to the internal organs. Pancreas The pancreas is a gland organ in the digestive system and endocrine system.

It is both an endocrine gland—producing several important hormones, including insulin, glucagon, somatostatin, and pancreatic polypeptide—and a digestive organ—secreting pancreatic juice containing digestive enzymes that help with the absorption of nutrients and digestion in the small intestine. These enzymes help to break down the carbohydrates, proteins, and fats. Ovaries The ovary is an ovum-producing reproductive organ, often found in pairs in the female reproductive system. Ovaries in women are analogous to testes in males—they are both gonads and endocrine glands. Our ovaries produce estrogen, progesterone, relaxin and inhibin. Testes The testicle is the male gonad. Like the ovaries in women to which they are homologous, testes are components of both the reproductive system and the endocrine system. The primary functions of the testes are to produce inhibin, sperm (spermatogenesis) and androgens, primarily testosterone. Hormones Hormones are powerful chemical messengers that our endocrine system uses to control various processes in our body. Hormones can be fat-soluble or water-soluble.

Endocrine glands secrete hormones into the blood stream near them; the hormones then travel in our bloodstream until it reaches its destination, called a target cell, in distance parts of the body. In the target tissue, hormones lock onto the target’s plasma membrane, called the receptor site. This chemical changes inside the target cells and adjusts the rate at which a specific action happens, such as a contraction of the muscle. Hormones can have one target or several targets. Hormones are released when they get feedback from triggers. Some hormones work on specific cells while other hormones work throughout the body. The level of hormones in the body are controlled by feedback. It is important that the amount of hormones in our body is kept at the right level. If hormone levels get too high or too low, they can make us sick. Although hormones come in contact with many cells in the body, they only react with target cells. A hormone can have more than one target cell, and can have different effects on different targets. Luteininzing Hormone This is a pituitary hormone that helps regulate the function of the reproductive organs. It stimulates ovulation to release the egg in the woman’s ovaries. In men it triggers the testes to produce male reproductive hormones.

Prolactin This is a pituitary hormone that stimulates the production of milk in the breast. It is one of several hormones that stimulate milk production or lactation. Breast-feeding stimulates the pituitary gland to make more prolactin so that milk is made for as long as the baby breastfeeds. Oxytocin Oxytocin is a pituitary hormone that stimulates muscle contractions in the uterus during childbirth. These contractions cause the release of more oxytocin. This is a positive feedback reaction that makes the cycle continue until the baby is born. Oxytocin also stimulates the breasts to release milk when the baby feeds. Glucagon The hormone glucagon increases the level of sugar in the blood. It plays a vital part in maintaining the correct blood sugar level. It is made by the pancreas, a gland that is part of the endocrine system and the digestive system. The pancreas releases glucagon when the blood sugar level starts to fall. Glucogon makes cells release glucose, and helps convert glycogen, the form of glucose stored in the liver, back to glucose. As a result the blood sugar level rises. Your blood has enough glucose to keep you alive for just 15 min.

However, as glucose is used up, more is released to take its place. Reproductive Hormones Reproductive hormones control the reproductive development of boys and girls. The development of primary and secondary characteristics and regulate all reproductive related processes such as sperm and egg production. Primary reproductive characteristics are the development of the major reproductive organs. There are 3 main types of reproductive hormones—androgens, estrogen, and progesterone. Female Reproductive Hormone Estrogen is the female hormone made mainly in the ovaries. It not only makes the girl reproductive organs develop, and controls her monthly menstrual cycle. Progesterone is the female hormone that prepares the girls uterus for pregnancy every month. Some contraceptive pills have estrogen in them to prevent the ovaries from releasing their egg cells. Male Reproductive Hormone The male reproductive system consists of the penis, scrotum, and the 2 testes. A male reproductive system creates sperm cells that combined with a female egg to create a new human life. The testes and scrotum hang outside the body where it is cooler because it improves sperm production. Sperm cells look like microscopic tadpoles. Sperm is made in the testes, which are inside the scrotum.

Sperm cells leave the testes through epididymis. The epididymis connects to the vas deferens. Glands called seminal vesicles lie along the vas deferens and add fluids and nutrients to the sperm. The male reproductive system also produces the reproductive hormones needed to make sperm and for a boy to develop at puberty. The male reproductive hormone testosterone also stimulates bone and muscle growth Epinephrine Epinephrine is a hormone that works with out nervous system to prepare our body to cope with danger or stress. If you’re suddenly scared, your heart pounds, your breathing becomes steep and rapid. These are just two of the effects of epinephrine, also called adrenaline. Epinephrine is a very fast acting hormone that prepares our body for emergency action—also called the fight or flight reflex. It speeds up our breathing and heart rate and diverts extra blood to the muscles. At the same time it slows down digestion and makes the liver release glucose into the bloodstream so more fuel is available for the muscles to contract. Insulin Insulin is a hormone that reduces the level of sugar in our blood. Insulin is a protein made by the pancreas.

It is released when the blood sugar level rises and reduces the sugar in 2 ways. First it makes insulin take up the glucose. 2nd in makes the liver store glucose by turning it into glycogen. Insulin and glucagon have opposite effects. Together they form a negative feedback system that keep sugar levels within set limits. In people with diabetes this control system does not work properly and they made may need daily injections of insulin to keep their blood glucose levels within safe limits. Growth Hormone The growth hormone is a pituitary hormone that controls the body’s growth by stimulating cell division. It also increases the blood glucose level. If your body has too little growth hormone, the body fails to grow normally. Too much growth hormone can cause the body to grow more than usual. Thyroid-stimulating Hormone The thyroid stimulating hormone makes the thyroid gland produce thyroid hormones. Adrenocorticotrophic Hormone This hormone stimulates the adrenal glands to produce other hormones. Antidiuretic Hormone This pituitary hormone increases the amount of water in the blood. A diuretic is a substance that stimulates the body to produce urine by taking water out of the blood stream.

The antidiuretic hormone or vasopressin, have the opposite effect. It increases the amount of water that the kidneys return to the blood and makes arterioles constrict. As a result, more fluid is squeezed into a smaller space and blood pressure rises. Follicle-stimulating Hormone This hormone and the Luteininzing Hormone are used in reproduction in both men and women. They also affect the production of reproductive hormones. Growth Hormone The growth hormone encourages growth in children and teenagers, makes our bones stronger, and helps build muscle. Growth is controlled by hormones produced by the pituitary gland. Oxytocin Hormone Oxytocin encourages childbirth and makes the breasts release milk when breast-feeding a baby. Prolactin Hormone You & Your Hormones | Hormones | Insulin You & Your Hormones Email article to a friend | Last updated: February 19, 2015 Insulin is an essential hormone produced by the pancreas. Its main role is to control glucose levels in our bodies. Diabetic person being injected with insulin to regulate their blood sugar levels. What is insulin?

Insulin is a hormone made by an organ located behind the stomach called the pancreas . Here, insulin is released into the bloodstream by specialised cells called beta-cells found in areas of the pancreas called islets of Langerhans (the term insulin comes from the Latin insula meaning island). Insulin can also be given as a medicine for patients with diabetes because they do not make enough of their own. It is usually given in the form of an injection. Insulin is released from the pancreas into the bloodstream. It is a hormone essential for us to live and has many effects on the whole body, mainly in controlling how the body uses carbohydrate and fat found in food. Insulin allows cells in the muscles, liver and fat ( adipose tissue ) to take up sugar (glucose) that has been absorbed into the bloodstream from food. This provides energy to the cells. This glucose can also be converted into fat to provide energy when glucose levels are too low. In addition, insulin has several other metabolic effects (such as stopping the breakdown of protein and fat). How is insulin controlled? When we eat food, glucose is absorbed from our gut into the bloodstream. This rise in blood glucose causes insulin to be released from the pancreas.

Proteins in food and other hormones produced by the gut in response to food also stimulate insulin release. However, once the blood glucose levels return to normal, insulin release slows down. In addition, hormones released in times of acute stress, such as adrenaline , stop the release of insulin leading to higher blood glucose levels. The release of insulin is tightly regulated in healthy people in order to balance food intake and the metabolic needs of the body. Insulin works in tandem with glucagon , another hormone produced by the pancreas. While insulin’s role is to lower blood sugar levels if needed, glucagon’s role is to raise blood sugar levels if they fall too low. Using this system, the body ensures that the blood glucose levels remain within set limits, which allows the body to function properly. What happens if I have too much insulin? Diabetic patients are given drugs including insulin treatment to lower their high glucose levels. However, if a person accidentally injects too much insulin, cells will take in too much glucose from the blood. This leads to abnormally low blood glucose levels (hypoglycaemia). The body reacts to hypoglycaemia by releasing stored glucose from the liver in an attempt to bring the levels back to normal.

However, persistently low glucose levels in the blood can make a person feel ill. Unlike other cells in the body, nerve cells depend almost entirely on glucose as a source of energy. When the glucose level is too low, the majority of the symptoms result from these nerves not functioning properly. The brain is particularly affected by low glucose levels. Symptoms include dizziness, confusion and even coma in severe cases. In addition, the body mounts a 'fight-back' response through a specialised set of nerves called the sympathetic nervous system. This causes palpitations, sweating, hunger, anxiety, tremor and a pale complexion. What happens if I have too little insulin? This is commonly seen in people with diabetes and is caused by different pathways in type 1 diabetics compared with type 2 diabetics. In some people, the pancreas is unable to make enough insulin, for example, in a condition called type 1 diabetes . This condition is caused when the beta cells that produce insulin have been destroyed. With too little insulin, the body can no longer move glucose from the blood into the cells, causing high blood glucose levels. If the glucose level is high enough, excess glucose spills into the urine.

This drags extra water into the urine causing more frequent urination and thirst. This leads to dehydration which can cause confusion. In addition, with too little insulin, the cells cannot take in glucose for energy. Other sources of energy (such as fat and muscle) are needed to provide this energy. This makes the body tired and can cause weight loss. If this continues, patients can become very ill. This is because the body attempts to make new energy from fat and causes acids to be produced as waste products. Ultimately, this can lead to coma and death if medical attention is not sought. Type 2 diabetes can be caused by two factors. Firstly, the patient’s beta cells may have an impaired ability to manufacture insulin. This means that while some insulin is produced, it is not enough for the body’s needs. Secondly, the insulin receptors, which allow insulin to exert its effects on individual cells, become insensitive and stop responding to the insulin in the bloodstream. A combination of these factors leads to similar symptoms as seen in type 1 diabetes.

Physiologic Effects of Insulin Glossary Physiologic Effects of Insulin Stand on a streetcorner and ask people if they know what insulin is, and many will reply, "Doesn't it have something to do with blood sugar?" Indeed, that is correct, but such a response is a bit like saying "Mozart? Wasn't he some kind of a musician?" Insulin is a key player in the control of intermediary metabolism, and the big picture is that it organizes the use of fuels for either storage or oxidation. Through these activities, insulin has profound effects on both carbohydrate and lipid metabolism, and significant influences on protein and mineral metabolism. Consequently, derangements in insulin signalling have widespread and devastating effects on many organs and tissues. The Insulin Receptor and Mechanism of Action Like the receptors for other protein hormones, the receptor for insulin is embedded in the plasma membrane. The insulin receptor is composed of two alpha subunits and two beta subunits linked by disulfide bonds. The alpha chains are entirely extracellular and house insulin binding domains, while the linked beta chains penetrate through the plasma membrane. The insulin receptor is a tyrosine kinase.

In other words, it functions as an enzyme that transfers phosphate groups from ATP to tyrosine residues on intracellular target proteins. Binding of insulin to the alpha subunits causes the beta subunits to phosphorylate themselves (autophosphorylation), thus activating the catalytic activity of the receptor. The activated receptor then phosphorylates a number of intracellular proteins, which in turn alters their activity, thereby generating a biological response. Several intracellular proteins have been identified as phosphorylation substrates for the insulin receptor, the best-studied of which is insulin receptor substrate 1 or IRS-1. When IRS-1 is activated by phosphorylation, a lot of things happen. Among other things, IRS-1 serves as a type of docking center for recruitment and activation of other enzymes that ultimately mediate insulin's effects. A more detailed look at these processes is presented in the section on Insulin Signal Transduction . Insulin and Carbohydrate Metabolism Glucose is liberated from dietary carbohydrate such as starch or sucrose by hydrolysis within the small intestine , and is then absorbed into the blood. Elevated concentrations of glucose in blood stimulate release of insulin, and insulin acts on cells thoughout the body to stimulate uptake, utilization and storage of glucose.

The effects of insulin on glucose metabolism vary depending on the target tissue. Two important effects are: 1. Insulin facilitates entry of glucose into muscle, adipose and several other tissues. The only mechanism by which cells can take up glucose is by facilitated diffusion through a family of hexose transporters . In many tissues - muscle being a prime example - the major transporter used for uptake of glucose (called GLUT4) is made available in the plasma membrane through the action of insulin. When insulin concentrations are low, GLUT4 glucose transporters are present in cytoplasmic< vesicles, where they are useless for transporting glucose. Binding of insulin to receptors on such cells leads rapidly to fusion of those vesicles with the plasma membrane and insertion of the glucose transporters, thereby giving the cell an ability to efficiently take up glucose. When blood levels of insulin decrease and insulin receptors are no longer occupied, the glucose transporters are recycled back into the cytoplasm. The animation to the right depicts how insulin signalling leads to translocation of glucose transporters from the cytoplasm into the plasma membrane, allowing glucose (small blue balls) to enter the cell. Click on the "Add Glucose" button to start it.

It should be noted here that there are some tissues that do not require insulin for efficient uptake of glucose: important examples are brain and the liver. This is because these cells don't use GLUT4 for importing glucose, but rather, another transporter that is not insulin-dependent. 2. Insulin stimulates the liver to store glucose in the form of glycogen. A large fraction of glucose absorbed from the small intestine is immediately taken up by hepatocytes, which convert it into the storage polymer glycogen. Insulin has several effects in liver which stimulate glycogen synthesis. First, it activates the enzyme hexokinase, which phosphorylates glucose, trapping it within the cell. Coincidently, insulin acts to inhibit the activity of glucose-6-phosphatase. Insulin also activates several of the enzymes that are directly involved in glycogen synthesis, including phosphofructokinase and glycogen synthase. The net effect is clear: when the supply of glucose is abundant, insulin "tells" the liver to bank as much of it as possible for use later. A well-known effect of insulin is to decrease the concentration of glucose in blood, which should make sense considering the mechanisms described above.

Another important consideration is that, as blood glucose concentrations fall, insulin secretion ceases. In the absense of insulin, a bulk of the cells in the body become unable to take up glucose, and begin a switch to using alternative fuels like fatty acids for energy. Neurons, however, require a constant supply of glucose, which in the short term, is provided from glycogen reserves. When insulin levels in blood fall, glycogen synthesis in the liver diminishes and enzymes responsible for breakdown of glycogen become active. Glycogen breakdown is stimulated not only by the absense of insulin but by the presence of glucagon , which is secreted when blood glucose levels fall below the normal range. Insulin and Lipid Metabolism The metabolic pathways for utilization of fats and carbohydrates are deeply and intricately intertwined. Considering insulin's profound effects on carbohydrate metabolism, it stands to reason that insulin also has important effects on lipid metabolism, including the following: Insulin promotes synthesis of fatty acids in the liver. As discussed above, insulin is stimulatory to synthesis of glycogen in the liver. However, as glycogen accumulates to high levels (roughly 5% of liver mass), further synthesis is strongly suppressed.

When the liver is saturated with glycogen, any additional glucose taken up by hepatocytes is shunted into pathways leading to synthesis of fatty acids, which are exported from the liver as lipoproteins. The lipoproteins are ripped apart in the circulation, providing free fatty acids for use in other tissues, including adipocytes, which use them to synthesize triglyceride. Insulin inhibits breakdown of fat in adipose tissue by inhibiting the intracellular lipase that hydrolyzes triglycerides to release fatty acids. Insulin facilitates entry of glucose into adipocytes, and within those cells, glucose can be used to synthesize glycerol. This glycerol, along with the fatty acids delivered from the liver, are used to synthesize triglyceride within the adipocyte. By these mechanisms, insulin is involved in further accumulation of triglyceride in fat cells. From a whole body perspective, insulin has a fat-sparing effect. Not only does it drive most cells to preferentially oxidize carbohydrates instead of fatty acids for energy, insulin indirectly stimulates accumulation of fat in adipose tissue.

Other Notable Effects of Insulin In addition to insulin's effect on entry of glucose into cells, it also stimulates the uptake of amino acids, again contributing to its overall anabolic effect. When insulin levels are low, as in the fasting state, the balance is pushed toward intracellular protein degradation. Insulin also increases the permiability of many cells to potassium, magnesium and phosphate ions. The effect on potassium is clinically important. Insulin activates sodium-potassium ATPases in many cells, causing a flux of potassium into cells. Under certain circumstances, injection of insulin can kill patients because of its ability to acutely suppress plasma potassium concentrations. Insulin Deficiency and Excess Diseases Diabetes mellitus, arguably the most important metabolic disease of man, is an insulin deficiency state. It also is a significant cause of disease in dogs and cats. Two principal forms of this disease are recognized: Type I or insulin-dependent diabetes mellitus is the result of a frank deficiency of insulin. The onset of this disease typically is in childhood. It is due to destruction pancreatic beta cells, most likely the result of autoimmunity to one or more components of those cells. Many of the acute effects of this disease can be controlled by insulin replacement therapy.

Maintaining tight control of blood glucose concentrations by monitoring, treatment with insulin and dietary management will minimize the long-term adverse effects of this disorder on blood vessels, nerves and other organ systems, allowing a healthy life. Type II or non-insulin-dependent diabetes mellitus begins as a syndrome of insulin resistance. That is, target tissues fail to respond appropriately to insulin. Typically, the onset of this disease is in adulthood. Despite monumental research efforts, the precise nature of the defects leading to type II diabetes have been difficult to ascertain, and the pathogenesis of this condition is plainly multifactorial. Obesity is clearly a major risk factor, but in some cases of extreme obesity in humans and animals, insulin sensitivity is normal. Because there is not, at least initially, an inability to secrete adequate amounts of insulin, insulin injections are not useful for therapy. Rather the disease is controlled through dietary therapy and hypoglycemic agents. Hyperinsulinemia or excessive insulin secretion is most commonly a consequence of insulin resistance, associated with type 2 diabetes or the metabolic syndrome. More rarely, hyperinsulinemia results from an insulin-secreting tumor (insulinoma) in the pancreas.

Hyperinsulinemia due to accidental or deliberate injection of excessive insulin is dangerous and can be acutely life-threatening because blood levels of glucose drop rapidly and the brain becomes starved for energy (insulin shock).

Question: Which organ of the body secretes insulin
Answer: Pancreas